Embodiments of the invention generally relate to environmental medicine, occupational health, industrial hygiene, emergency medicine, ophthalmology, first responder eye protection, and the like. In particular, various aspects of the invention relate to an eyewash or eye drops, both referred to herein as a collyrium, for deactivating irritant and pollutant gases that readily adsorb to exposed ocular tissues, periocular fluids, or contact lenses is particularly useful. When deactivated, these reactive gases have an improved water solubility which enables their removal by aqueous irrigation and rinsing.
The oxidation or combustion of substances can be rapid or slow. Rapid oxidations produce fire, heat, light, and gases. In contrast, rusting iron and biological oxidation examples are slow oxidations; they ordinarily do not display typical evidence of fire, such as heat and light.
Rapid oxidations begin when a combustible material is exposed to an energy source such as heat, electricity, radiation, and the like. When the energy source provides sufficient energy so as to raise the temperature above a unique ignition temperature, the combustible material begins to oxidize or burn without further additional external energy.
One of the simplest and most complete oxidation reactions is exemplified by the reaction of hydrogen and oxygen. These elements readily combust to produce water and heat:2H2+O2→2H2O+Heat  (1)Due to the reaction's exothermic nature, the intense release of heat vaporizes newly formed water into steam. This rapid combustion reaction is then complete and the reaction is simple and predictable.
In the absence of controlled laboratory conditions, even the complete oxidation reaction involving hydrogen and oxygen can be difficult to forecast. As combustion reactions proceed under typical ambient conditions, a bewildering array of products can develop. While some obvious combustion products are favored, many minor and trace products can also form. These products may be totally unpredictable or reflect the unique presence of elements within the combustible material. Some of these products may or may not exhibit toxicity.
Whatever the combustion model, the final mixture of reaction products will be influenced by:                (a) Molar amounts of constituent atoms present in the combustible materials;        (b) Thermodynamic conditions driving atomic reactions at the instant of combustion; and/or,        (c) Physical conditions directing equilibria as post-combustion atomic species combine to achieve thermodynamic stability.Many of these factors are so transient that it may not be possible to predict all combustion products with certainty.        
Since combustible organic materials usually include high percentages of carbon atoms, post-combustion equilibrium products favor oxides of carbon. These usually include carbon monoxide (CO) or carbon dioxide (CO2) when combustion occurs under ambient atmospheric conditions.
With vigorous combustion, however, a deficit of oxygen (or oxidizer) favors the formation of partially oxidized carbon which can include soot, ash, or smoke. Furthermore, combustion reactions in air having 78% nitrogen, will promote the added development of nitrogen oxides (NO) and cyanide (CN), while the presence of trace levels of sulfur in the air can result in the formation of sulfur oxides (SOx). Therefore, regardless of the elemental simplicity of reactions involving hydrocarbons based on carbon and hydrogen, the presence of typical atmospheric gases or components can result in the formation of several complicated combustion products.
Survival instincts or autonomic reflexes usually minimize the voluntary inhalation of irritant combustion products which can be responsible for carcinogenic, toxigenic, or irritant respiratory damage. Ocular tissues, including the lens, conjunctiva, and periocular membranes, however, are relatively unprotected from combustion gas product exposures, and they are also liable to chemical attack. While immediate molecular damage to these structures by reactive gases is possible, a cascade of poorly defined secondary reactions often results in delayed tissue damage.
When moist eyes are exposed to reactive gases, eye discomfort is typically described as a burning, dull pain with grittiness, or the feeling of “something in my eye.” Few remedies work quickly enough for locating and eliminating the source of such uncomfortable and inaccessible sensations.
While the globe of the eye itself may be a direct pain source, combustion gases are also dispersed over the periocular tissues, which further complicate irritant sensations. Notwithstanding any abrasive effects caused by particulates, eye discomfort is also complicated by pH-induced effects as reactive gases interact with moist ocular membranes.
Because gas combustion products often include acidic anhydrides, these are rapidly converted into acids upon exposure to water such as found in and around the eye. For example, carbon dioxide, nitrogen dioxide, and sulfur dioxide each develop their corresponding acids such as carbonic acid, nitrous (nitric) acid, and sulfurous acid:CO2(g)+H2O(1)→H2CO3(aq)  (2)NO2(g)+H2O(1)→HNO2(aq)+HNO3(aq)  (3)SO2(g)+H2O(1)→H2SO3(aq)  (4)
Since water is readily available on ocular membranes and in tears, pKa-dictated acid properties effectively lower the pH of aqueous eye fluids. This action promotes an irritant effect over highly innervated ocular tissues along with increased lacrimation.
Typical threats due to fire and combustion products are often met with the urgency of survival. While sensations of smoke, heat, and fire prompt escape and avoidance responses, significant fire events release such large amounts of reactive gases that contact with them is often unavoidable.
Typical among these circumstances are natural gas, industrial, chemical, and wild or forest fires where large volumes of NO2, NO, SO2, and CN are produced. Threats from these gases are particularly serious for first-responders and others at fire scenes largely due to the increased use of synthetic combustible building materials made from or incorporating synthetic compositions including polyacrylonitrile, polyurethane, polyamide, and urea-formaldehyde.
Many of the most injurious gases cannot be avoided since more abundant volatiles mask their presence. In best case scenarios, tissue exposure to reactive gases may be limited by protective equipment, but too often the eyes and their related tissues are inadvertently exposed to biologically active and/or poisonous gases.
Thus, an effective emergency strategy for moderating unavoidable reactive pollutant gas effects on the eyes persists as an unmet need.
Typical treatments often rely on flushing the eyes with an aqueous fluid to displace foreign material. Unfortunately, this has little value for alleviating irritant and reactive gas effects on the eyes since gases interact in at least two ways upon eye contact. First, they adsorb to structural biochemical elements in the eye such as proteins and carbohydrates; and second, they initiate further reaction cascades that support cumulative sight-compromising outcomes if unchecked. Presently available collyria (i.e., eyewashes) fail to address either one of these issues.